Method of alumino-thermic pressure welding



May 29, 192s. 1,671,730

F. LANGE METHOD OF ALUMINO THERMIC`PRESSURE-WELDING Filed May 28, 1927-hlsatented-May 29, -1.92.8. p A y UNIT-ED STATES PATENT OFFICE.

FELIX LANGE. F BERLIN LANKWITZ, GEBIANY.

METHOD 0F VALUMIN'O-'I..`Hls`|BIM`.I(`2 PRESSURE WELDING.

Application filed Iay 28, 1927, Serial No. 195,093, and in GermanySeptember 17, 1926.

The invention relates to a novel method of exothermic pressure weldingor butt welding elements, such as railway rails and the like, and hasfor its object to so apply the products of .the exothermic reaction tothe,

parts to bewelded under pressure as to insure a substantially uniformheating of the' partsto welding temperature.

The-usual practice'of pressure welding or butt welding elements, such asrails, by the alumino-thermic process. is. to enclose the ends of theelements to be welded in a mold of suitable form to provide a spacecompletelysurrounding the ends of the elements, into which space thesuperheated product of the alumino-thermic reaction, which has beenproduced in a separate crucible, 4is poured to heat'the elements towelding temperature, the finished welds being produced by forcing theelements together under pres# sure, The practice of this method,however, involvesa relatively large loss of heat, be-

cause the reaction ,of the alumino`thermic mixture is elected in aseparate crucible and the superheated metal mustbe teemed from .thecrucible into the mold. An alternatife procedure has beensuggested,namely, ,to eiect the 'alumino-thermic reaction in the i mold, butlthismethod has proven diilcult and 4even ineffective in many instances,because of the inabilityto charge a suiicient quantity of thealuminosthermic mixture into the mold, more especially'inthelowerportions of the mold space, such, for ex? ample, as that lying belowrthebases of railrails and like'elements to be` welded.

wayl A", rther objection to this particuar method is'tha't the roductsof the alumino-t-hermic reaction w ich gis carried out inside ofthe ymold, `frequently produce excessive local heating of the arts-to bewelded, which results in the me ting or washing away of the 'parts,.more especially the thinner Asections "andlp'rotruding edges, andresultant fusion of the-alumino-thermie iron or steel with the metal ofthe. rails or other elements Vto 'be welded,`thereby unduly increasingthe cross sections of the fparts'and, in some instances,

completely d e rming vthe parts, thereby nulhfying the main advantage ofthe butt or pressureweld, as 4com ared with the.

fusion weld or the combin fusion and pressure weld. Accordingvto thepresent inven-v tion,`the diiculties and objections inherent in both ofthe former methods yofalui'ninothermic pressure welding'are obviated anda large economic advantage is gained, first, Iin` the conservation ofthe heatproduced by the aluxnino-thermic reaction, and second, by theproduction of an ellicient and effective butt or pressure weld betweenthe elements. This result is obtained by enclosing the ends of theelements, such as the rails, 1n a mold 'which provides a spacesurrounding the enclosed ends of the elements', supplying the upper partof the mold cavity with the alumino-thermic mixture, charging the lowerpart of .the cavity with the superheated metal and slag resulting fromthe alumino-thermic lreaction carried out in-a separate crucible andtapped into the mold through a' pou-ring gate communicating with thebottom part of the mold, and finally pressing the heated elementstogether to veffect the Vpressure or butt weld.

A simple means for carrying out 'the accompanying .lower portion ofthespace below the base being indicated at c, and the upper and lowerportions' of the space or cavity being connected by relatively narrowchannels e. Connecting the' upper part of the mold with the 1;werspace cofthe cavity is a pouring gate .Incarrying out ythe invention,.theportion of the mold, cavity or space d is supplied with the requisiteantity of aluminothermic mixture, whidli-.may completely surround andembed the ends of the rails above which is a transverse sectional ele- 1the bases .of the latter. A .suilicient quantity 'of alumina-thermicmixture is then brought to reaction in,` a suitable crucible and thes'uperheated metal and slag resulting from the reaction is poured intothe mold through-the gate f, enters and fills the-space c, and asullclent portion of the superheated product passes by way of thechannelsA e into contact with thev alumina-thermicmixture in the moldcavity d, thereby ,igniting the mix- 'ture and'causinhe' same to react,the heat of the reaction ing suicient to bring the ilo A l force theabutting ing the upper arately prepared, and preing the heated elementstogether.

2. The method of making alnmino-thermic pressure welds, which comprises,enclosing the elements to be welded ini' mold, supplyart of the moldcavity surrounding said e ements with aluminofthermc mixture, cha 'ngthe lower part of the cavity with lique ed alumino-thermic meltseparately prepared, and pressing the heated elements together.

In testimony whereof I aix my signature.

FELIX LANGE.'

